Merge pull request swiftlang#31165 from xymus/print-less-objc-imports

[PrintAsObjC] Don't print imports for empty extensions

Author: xymus

lib/PrintAsObjC/ModuleContentsWriter.cpp

@@ -400,6 +400,9 @@ class ModuleWriter {
   }
 
   bool writeExtension(const ExtensionDecl *ED) {
+    if (printer.isEmptyExtensionDecl(ED))
+      return true;
+
     bool allRequirementsSatisfied = true;
 
     const ClassDecl *CD = ED->getSelfClassDecl();

test/PrintAsObjC/Inputs/custom-modules/MiserablePileOfSecrets.h

@@ -3,3 +3,6 @@
 @interface NSObject (Secrets)
 - (void)secretMethod;
 @end
+
+@interface SecretClass : NSObject
+@end

test/PrintAsObjC/imports.swift

@@ -67,3 +67,7 @@ import MostlyPrivate2_Private
 @objc public class TestSubclass: NSObject {
   @_implementationOnly public override func secretMethod() {}
 }
+
+extension SecretClass {
+  private func somethingThatShouldNotBeIncluded() {}
+}